Answer:
A. 0
Step-by-step explanation:
3ab+5b-6
= 3(-1)(3)+5(3)-6
=3(-3)+15-6
=-9+9
=0 ( you have to subtract because they don't have the same signs)
Answer:
Your missing a number and your answer is 12
Step-by-step explanation:
<span> |2x − 5| − 2 = 3
</span><span>1) |2x − 5| = 3 +2
2)</span><span> |2x − 5| = 5
3) 2x-5 = 5, or 2x-5= -5
4)2x=10, or 2x=0
5) x = 5 , or x = 0
Check:
</span> |2x − 5| − 2 = 3
|2*5− 5| − 2 = 3 or |2*0 − 5| − 2 = 3
|5|-2=3 or |-5| -2 =3
3=3 (true) or 3=3 (true)
All steps are correct.
Elimination:
7x - 3y = 20
5x + 3y = 16
(add)
12x = 36
÷ 12
x = 3
(5 × 3) + 3y = 16
15 + 3y = 16
- 15
3y = 1
÷ 3
y = 1/3
Substitution:
5x + 3y = 16
- 3y
5x = 16 - 3y
÷ 5
x = 3.2 - 0.6y
5(3.2 - 0.6y) + 3y = 16
16 - 3y + 3y = 16
16 = 16
- 16
6y = 0
÷ 6
y = 0
Sorry the substitution messed up for some reason, I'll fix it after I've answered the other question
Answer:
Internal validity
Step-by-step explanation:
The internal validity here is weak
Internal validity describes the extent to which an evidence weighs the cause and effect claim. In this study, the internal validity that brought about failure in the new exam is mainly due to the environment where the exam was written and not the new exam itself.
So this validity is weak in claiming that the new exam is not a good substitute for the old exam.
Putting them in the same good environment might help the researchers to draw a better conclusion.
